Fertigation effects on the concentration of mineral components in the soil and leaves, and the yield and quality of fruits in two apple-tree cultivars

An experiment was carried out from 1994-1998. The experimental material consisted of apple trees of ampion and Golden Delicious cultivar (Malus domestica Bork.), budded on M.26 rootstock. The trees were planted in autumn 1990. A fertigation system was established in spring of 1991. Soil moisture was maintained at 0.03 MPa of soil water potential. The following fertilization combinations were applied: 1- no N fertilization, 2 - 5 g N/under tree, 3 - 10 g N/under tree, 4 - 15 g N/under tree, 5 - 5 g N/m (fertilizer was top dressed). Additionally, a control combination without fertilization and irrigation was included. In soil samples the values of P, K, Mg and pH were determined. In leaf samples the concentration of N, P, K, Mg and Ca were measured. Results indicated a change in the chemical composition of the soil resulting from leaching of K and P ions from the soil. The applied irrigation and fertigation treatments did not cause any change in soil reaction. A negative correlation was measured between the yield of ampion cultivar and the potassium content in the leaves. Fertilization with nitrogen contributed to an increased concentration of N and K in the leaves and to a decreased concentration of calcium. Linear correlation analysis indicated that the calcium concentration in the leaves was positively correlated with mean temperature during the growing season.